The present invention generally relates to buoyant floats, and more particularly, to a buoyant hollow float having features for preventing liquid from entering an interior of the float.
Liquid condensate forms in many gaseous fluid handling systems. In order to ensure proper system operation, the condensate is usually separated from the gas (e.g., by gravity) and collected along with solid foreign materials in a reservoir. The accumulated liquid and materials are periodically discharged to prevent the reservoir from becoming too full, causing system backup or reservoir overflow.
Various drain systems have been used to discharge the liquid and foreign materials. One such drain system is described in U.S. Pat. No. 5,983,919, which is incorporated by reference. Typically, the drain system is fluidly connected to the reservoir. A float in the system rises and falls in response to the liquid level in the reservoir. When the float rises to a predetermined maximum level, the drain valve opens. In many cases, the float opens a pneumatic valve that permits gas in the reservoir to actuate a separate drain valve at the bottom of the reservoir to drain the accumulated liquid and foreign materials. Often filtered and dried shop air is used as the pressurized gas. This pressurized gas is introduced into the reservoir where it accumulates above the condensate.
Many systems use sealed, air tight, hollow floats, particularly when the gas in the reservoir has a relatively low pressure. Higher gas pressures may be desirable to improve drain valve performance. When relatively high-pressure gas is introduced into the reservoir of a system using a hollow float, the gas pressure may crush the float if the pressure of gas in the float is not equalized to the pressure outside the float. To combat this problem, some systems such as that described in U.S. Pat. No. 5,983,919 use solid floats made from closed cell polyurethane foam, which can endure higher pressures without crushing. These solid floats, however, can become infiltrated with condensate, affecting their buoyancy and operation. The likelihood of condensate infiltration increases with gas pressure. Thus, various features have been added to hollow floats to balance pressure inside the float with pressure outside the float. For example, openings may be provided near the top of the float to allow air to enter and escape the interior of the float. Although these features permit pressure balance in the float, condensate can also enter the hollow interior of the float through the opening, increasing float weight and hindering operation. Thus, there is a need for a hollow float having features that permit pressure balance while preventing condensate from entering the float.